1. Field of the Invention
The present invention relates to a tool exchange apparatus which is installed in a machine tool and has a tool magazine for holding a plurality of tools, and which exchanges the tool held by the tool magazine for the tool installed in a main spindle.
2. Description of the Prior Art
Usually, a tool exchange apparatus is installed in a machine tool such as a machining center for exchanging a tool attached to a main spindle for another tool. There are two types in the tool magazine of such tool-exchange apparatus. One is formed of a plurality of tool pots installed in an endless chain. Another is formed of a plurality of tool pots installed in a disk-shaped pot supporter. The tool-exchange apparatus having the former transfers a tool pot installed in an endless chain to the tool exchange position in the machine tool then exchanges the present tool installed in the main spindle for the next tool held by the tool pot. Further, the tool-exchange apparatus having the latter rotates a disk-shaped pot supporter, which supports a plurality of tool pots thereon in an annular and radial manner with tips of the tools projecting out of the circle of the pot supporter outwards, to a designated angle then indexes the tool pot holding the next tool to the indexing position for exchanging the tools. There is another disk-shaped pot supporter that supports a plurality of tool pots thereon in an annular manner with tips of the tools projecting out of the surface of the pot supporter outwards in the normal line.
Thus, the tool-exchange apparatus in which the tool pots are installed in the endless chain can hold a greater number of tools. On the other hand, the tool-exchange apparatus in which the tool pots are installed in the pot supporter can speedily exchange by rotating the pot supporter at high speed so as to index the tool pots.
However, the former mentioned one type of tool-exchange apparatus can hold a large number of tools but the apparatus itself becomes large. Therefore there is a problem that a large space is necessary to install the tool-exchange apparatus in a machine tool, consequently a space to put the machine tool also becomes large. Therefore especially when constructing a manufacture line such as a transfer machine where a plurality of machine tools are arranged in a parallel manner, there is a problem that it takes long time to transfer a work and production efficiency decreases as a result. And there is another problem that an operator has to move a wide space, consequently causing a decrease of operation efficiency.
Further, among the later mentioned two types, one of tool-exchange apparatus holds the tools with tips of the tools projecting out of the circle of the pot supporter outwards, wherein the tools are held such that they project from the outer circumference of the pot supporter. Therefore the tool magazine is large and the area to install the machine tool becomes large, too, and as a result causing problems like the former mentioned tool-exchange apparatus. In the other type tool-exchange apparatus wherein the tools are held annularly erected on the pot supporter, the machine tool installing the tool magazine is so high although the area to install the machine tool doesn""t become large. And as a result making difficult a maintenance work as well as a detachment of the tools from the tool pots, consequently there is a problem that production efficiency is deteriorated.
Accordingly, it is a principal object of the present invention to solve above-mentioned problems.
Another important object of the present invention is to provide a tool-exchange apparatus which can decrease an area to install a whole machine tool and can make easy a detachment of tools as well as a maintenance of the apparatus itself.
In this invention according to claim 1 to attain above-mentioned objects, a tool-exchange apparatus for a machine tool includes a tool magazine defined of a plurality of tool pots that are arranged on the same circumference of a circle equally spaced away from each other. And each of the tool pots has the opening for putting the tool therein toward the center of the circle whereby the plurality of tools are held by the tool magazine in a radial manner. When the tool pot is indexed at an indexing position, the tool-exchange apparatus exchanges the present tool installed in the spindle for the next tool held by the tool magazine with the tip thereof looking toward the center of the circle.
In this invention, the tools are held by the tool magazine in a radial manner or centripetally in such condition that tips of the tools are directed toward the center of the circle when the tools are respectively put in each opening of a plurality of tool pots. Therefore, the tools held by the tool magazine never project outside of the tool pots of the tool magazine, whereby making the tool magazine itself compact.
Thus, according to the present invention, the tool magazine can be made compact because the tools held by the tool magazine don""t project outwardly, whereby a total size of the machine tool also can be made compact. As a result, an area to install the machine tool can be decreased. Therefore, when constructing a manufacture line such as a transfer machine, each machine tool can be arranged as closely as possible, an area to install the whole manufacture line can be decreased, as a result production efficiency can be improved.
Further, in the present invention according to claim 2, in a tool-exchange apparatus as set forth in claim 1, wherein the tool magazine is arranged above the work process area having the exchanging position of the spindle side in the machine tool and revolves the tool pots around the center of the circle within a horizontal plane for indexing the tool pots at the indexing position, further includes a transfer means for transferring the tool pot indexed at the indexing position to the exchanging position of the tool pot side which is located below the indexing position and a tool exchange arm which exchanges the present tool in the exchanging position of the spindle side for the next tool in the exchanging position of the tool pot side.
According to the present invention, the tool pot that holds the next tool is transferred to the exchanging position of the tool pot side located below the indexing position by the transfer means after being indexed at the indexing position by the revolution of the tool magazine in the horizontal plane above the work process area. Thereafter the tool exchange arm exchange the next tool held by the tool pot at the exchanging position of the tool pot side for the present tool installed in the spindle at the exchanging position of the spindle side in the work process area.
Thus, according to the present invention, above-mentioned tool magazine that is made compact is arranged so that it revolves in the horizontal plane in such area that the tool magazine is placed above the work process area and doesn""t interrupt a work processing. Therefore a width of the machine tool can be set as close to as that of the bed of the machine tool, consequently the width of the machine tool can be decreased. Even though the tool magazine is arranged above the work process area, the tool magazine doesn""t project much above the machine tool and the height of the machine tool can be decreased as a result, because the tool magazine holds the tool in a horizontal posture. Therefore, operator can easily detach the tools from the tool pot and do other maintenance work without difficulty. Further, because the tool magazine is arranged above the work process area, the operator can attach/detach the tool on/from the tool pot from the opposing side to the spindle (i.e. the front), as a result making easy the attachment and detachment of the tool.
Further, in the present invention according to claim 3, in the tool-exchange apparatus as set forth in claim 2 the transfer means comprising a engaging means in engagement with the tool pot for moving between the indexing position and the exchanging position of the tool pot side and an elevating means for moving the engaging means up and down between the indexing position and the exchanging position of the tool pot side. As a result making the tool pot not project from the side of the machine tool while transferring the tool pot indexed at the indexing position, consequently the area to install the machine tool can be decreased.